The economy of reloading used cartridges has long been known to participants in the shooting sports. Hand loaders have sought out and used reloading equipment for over a hundred years. The equipment whose commercial success has endured is inexpensive, reliable and safe.
The basic process of reloading ammunition consists of six operations; (1) punching out the spent primer; (2) swaging the cartridge to its unfired diameter with a die; (3) pressing in a new primer; (4) measuring a volume of powder and pouring it into the cartridge; (5) pressing a bullet into the cartridge mouth (or adding a measure of shot for shot shells). The equipment for performing these operations varies from simple hand tools to complex high speed commercial reloading machinery.
The area of invention addressed here is in the operation of measuring volumes of powder or shot and introducing them into cartridges. The requirements of the operation are an accurate measure of powder or shot and the ability to introduce it into the cartridge without spillage. Commercial reloading equipment meters a consistent charge by volume. Volumetric measuring works well and is in general use by reloaders because the alternative method of weighing every charge is too time consuming.
Consistent charges in each cartridge contribute to the accuracy of the ammunition. Overcharges in ammunition can be dangerous and cause excessive pressures in cartridges and firearms endangering the shooter.
To determine the appropriate charge, reloaders refer to data published by ammunition component manufacturers. A safe weight of powder or shot is specified for each combination of bullet or shot weight, powder, and expected velocity for each type of ammunition. Suppliers of volumetric powder measures provide data to convert weights of various brands and types of powder to equivalent volumetric measuring chambers and powder spoons. These means are then used to meter a consistent volume of powder and deposit it into the cartridge mouth. One cartridge is charged at a time. Care must be taken to avoid introducing more than one powder charge in each cartridge, since it is possible to do so with these devices. Charges of shot are handled in a similar manner, converting weight to volume.
In the search for reducing hand loading labor a multiple cartridge loading device, U.S. Pat. No. 506,425 dates from 1893. It consisted of a box fitted with sliding panels. The cartridges were placed in the bottom, mouth up, beneath spillways. A sliding solid panel was then slid in on top of the spillways followed by panels of varying thickness, and holes aligning with each other and the spillways. The desired charge volume was reached by choosing the right combination of panels with holes and sliding them over the solid panel. The powder or shot was poured over the holes filling them and the excess was raked off with a straight edge. Sliding out the bottom solid panel allowed the contents of the holes to flow into the cartridges below. The commercial success of this device is doubtful since it is not in common use today.